Selects the area for which the **force_element_edge_normal** record with
the same *index* should be applied.
By example, **-geometry_line 1** can be
used in 2D, indicating that the nodes on line 1 get the distributed force.

__Attention__: if this **force_element_edge_normal_geometry** option is used INSIDE
a FE mesh, then the elements on each side of the geometry will get the force.
So the total force will normally become zero since the normals of the elements
at the side of the geometry are opposite.

tochnog 2001-09-02